Color image forming apparatus having function of obtaining color information of patch

a color image and patch technology, applied in the field of color image forming apparatus, can solve the problems of long time to perform one measurement operation, colorimetric value error,
US20110217052A1Inactive Publication Date: 2011-09-08CANON KK
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Patent Information

Authority / Receiving Office
US ยท United States
Current Assignee / Owner
CANON KK
Publication Date
2011-09-08
Estimated Expiration
Not applicable ยท inactive patent

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Abstract

An image forming apparatus uses the difference in time taken for each patch to reach a color sensor, which occurs upon reversing the conveyance direction of a printing material. Due to this difference in time, the temperature of the printing material in detection by the color sensor differs among the respective patches. The error of a colorimetric value due to thermochromism is reduced by placing a patch with a colorimetric value which has a low temperature dependence so as to be detected earlier, and a patch with a colorimetric value which has a high temperature dependence so as to be detected later.
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Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a color image forming apparatus which forms a color image.

[0003] 2. Description of the Related Art

[0004] In recent years, a color image forming apparatus which is typified by, for example, a color printer and a color copying machine and adopts, for example, the electrophotographic or inkjet scheme must output higher-quality images. To meet this requirement, Japanese Patent Laid-Open No. 2003-084532 proposes a color image forming apparatus including a color sensor located downstream of a fixing unit. The color sensor irradiates a patch formed on a printing material with light to obtain its color value (color information) from the light reflected by it. The color image forming apparatus adjusts the tone of a toner image formed on the printing material, in accordance with the output from the color sensor.

[0005] Upon colorimetry of the patch formed on the printing material, the colorimetric val...

Claims

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